Note : Les descriptions sont présentées dans la langue officielle dans laquelle elles ont été soumises.
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Motor vehicle door lock
Description:
The invention relates to a motor vehicle door lock with a locking mechanism,
an actuation
lever unit with a release lever acting on the locking mechanism and a catch
lever, blocking
the locking mechanism at least when acceleration forces of a given magnitude
occur, e.g. in
case of an accident (crash).
The actuation lever unit generally comprises one or several levers. Normally,
the unit
contains at least an internal actuating lever, an external actuating lever and
a release lever.
In addition, the actuation lever unit also often contains a coupling lever.
When the actuation
lever unit is acted upon, the locking mechanism can be opened in this way. For
this purpose,
the release lever typically engages with a pawl of the locking mechanism and
lifts it off an
associated rotary latch. The rotary latch then opens with the assistance of a
spring and
releases an engaged locking bolt. As a result, an associated motor vehicle
door can be
opened.
In case of an accident or in the event of a crash, mentioned above, high
acceleration forces
generally occur, which can be several times greater than the earth's
acceleration. The
respective motor vehicle door lock is thus exposed to considerable inertia
forces which could
cause an unintentional opening of the locking mechanism and thus of the entire
associated
door lock.
These described scenarios represent considerable hazards for vehicle users. A
motor
vehicle door opened unintentionally can, for instance, no longer provide any
safety devices
contained therein, such as a side airbag or side impact protection for the
protection of the
passengers of the vehicle. For this reason, various measures were already
implemented in
the past that either block the actuation lever unit or the locking mechanism
during
occurrence of the described abnormal acceleration forces, e.g. in the event of
a crash. In
these cases, a so-called inertia lock is used, which is in its rest position
under normal
operating conditions and is not engaged in the actuation lever unit or the
locking mechanism.
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A catch lever acting on the actuation lever unit is, for instance, disclosed
in DE 197 19 999
A1. The lock or catch lever blocks an opening lever when the described
acceleration forces
are exerted in case of an accident. For this purpose, the lock or the catch
lever and the
opening lever are arranged transversely to the swivel direction of the opening
lever and are
displaceable in relation to each other. In case of a relative displacement
caused by
increased acceleration forces, the opening lever enters the lock. This aims to
prevent
unwanted opening in the event of a crash whilst keeping the design simple. A
permanent
blocking of the opening levers is also generally discussed.
The generic state of the art of DE 19910 513 A1 describes a crash catch on a
door lock. This
catch contains a pivotable catch lever, which can be pivoted by inertia force
around its swivel
axis into a blocking position stopping the transmission element.
Also, a counter blocking surface is provided, which is fixed in position.
Not all aspects of the prior art are satisfactory. The systems generally work
in that the catch
lever blocks the actuation lever unit or locking mechanism only during the
occurrence of
abnormal acceleration forces, e.g. in the event of a crash. In practical
application this can
result in incorrect functioning, for instance, in case that the movement of
the catch lever is
blocked or delayed due to corrosion or ageing, etc. Such functional faults can
also not be
checked, for instance, as part of maintenance, as the catch lever has to be
moved, which is
not possible in practical application. The invention aims to remedy this
situation.
The invention is based on the technical problem of further developing such a
motor vehicle
door lock in such a way that functional reliability is increased, whilst
keeping the design
simple.
To solve this technical problem, a generic motor vehicle door lock of the
invention is
characterised in that the catch lever in undisplaced standard operation and in
the event of a
crash acts upon a rotary latch for the locking mechanism in the direction of
the blocking
position (and thus also in the blocking position of the locking mechanism) and
only permits
the releasing position of the rotary latch and thus of the locking mechanism
in the displaced
standard operation.
As part of the invention, normal operation refers to the functional states of
the motor vehicle
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door lock in which only acceleration forces occur that correspond to the
normal driving
dynamic processes.
In contrast, accidents are in most cases associated with greater accelerations
and delays. In
this case reference is made below to abnormal acceleration processes or
abnormal
acceleration forces or the event of a crash or accident.
If such an accident or crash occurs, the catch lever ¨ in contrast to the
state of the art ¨
remains active, e.g. permanently active, as the catch lever is in its blocking
position in its
unactivated state and in standard operation as well as in the event of a
crash. In this
functional position the catch lever acts upon the rotary latch in the
direction of the blocking
position. In other words, the catch lever, the rotary latch and thus also the
locking
mechanism assume the blocking position during normal operation and in the
event of a
crash.
The catch lever permits the releasing position of the rotary latch and thus of
the locking
mechanism only during opening in the standard operation, with the catch lever,
the rotary
latch and thus the locking mechanism being in their respective releasing
position.
During the unactivated state in normal operation, a release lever of the
actuation lever unit
also does not act on the locking mechanism in an opening manner but rests in
this respect.
The release lever does thus not act on a pawl of the locking mechanism
consisting of a
rotary latch and pawl in the opening sense. In comparison to the locking
mechanism, the
actuation lever unit rests. In contrast, part of the opening in the normal
operation includes
that the release lever is deflected in order to deflect a blocking pawl and
lift the pawl off the
rotary latch. The rotary latch is consequently released from the pawl and can
move to its
open position with the assistance of a spring. A previously retained locking
bolt is released
again. As the locking bolt is typically connected to a motor vehicle door, the
motor vehicle
door is also released during this process.
During standard operation and in the event of a crash the catch lever as a
whole is
permanently active in its blocking position. The catch lever ensures, after
all, that the rotary
latch remains in its blocking position. In the event of a crash, the inertia
moment of the catch
levers ensure that the lever does not follow any movement of the actuation
lever unit and
can also not follow it and that, irrespective of the direction of the crash.
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lf, however, the actuation lever unit is acted upon during normal operation,
the catch lever is
deflected. This deflection of the catch lever allows that after actuation of
the blocking pawl
and pawl in its releasing position, the rotary latch is released from the pawl
and thus
releases the locking mechanism. The previously engaged rotary latch is
released as during
opening, the pawl is also lifted off the rotary latch. This means that each
opening process for
the locking mechanism corresponds as part of the invention to an actuation of
the catch
lever, which is moved from its blocking position into the releasing position.
Similarly this
applies to the blocking pawl and, of course, the pawl. As a result, each
normal actuating and
triggering process causes the catch lever to be moved. Any corrosion,
sticking, etc., as in the
state of the art, can thus not occur. The result is greater functional
reliability combined with a
simpler design.
In an advantageous embodiment, the catch lever is designed as a swivel lever
rotatable
around an axis. Typically, the catch lever is accommodated in a lock case
together with a
locking mechanism. It has also proven to be advantageous for the catch lever
to be
designed as a two arm lever consisting of a blocking arm and a compensation
arm.
Preferably, the blocking arm engages with the rotary latch in such a way that
the rotary latch
can be released for opening.
Generally, the catch lever is coupled to the release lever of the actuation
lever unit. An
elastic coupling has proven to be particularly advantageous as in this case
and, in particular,
in case of a crash, the catch lever can remain at rest whilst any movements of
the actuation
lever unit are permitted. Such movements of the actuation lever unit are,
however, not
transferred to the catch lever or to the locking mechanism blocked by it.
In detail, the catch lever and the release lever are connected with each other
by at least one
spring. The spring can engage with the blocking arm of the catch lever. To
open the locking
mechanism, the release lever is acted upon in such a way that it activates the
blocking pawl
and lifts the pawl off the closed rotary latch. During this process, the
release lever acts at the
same time on the catch lever elastically coupled with said lever by means of
the spring. In
order for the catch lever to be able to release the rotary latch during this
process, the catch
lever may contain a blocking shape interacting with the rotary latch, a cam, a
deformation,
etc. At the same time, the play between the catch lever and the rotary latch
is dimensioned
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in such a way that the described process can easily occur.
This means that the catch lever interacts advantageously with the rotary
latch. The pawl
itself engages with the rotary latch of the locking mechanism. For this
purpose, the pawl can
be arranged on the actuation lever unit.
As soon as the locking mechanism or the rotary latch moves into its closed
state by the
locking bolt moving into the rotary latch, the pawl does not only engage in
the arrangement
of the invention but the blocking pawl also moves into its blocking position.
Any movement of
the actuation lever unit do thus not result in an opening of the locking
mechanism until the
blocking pawl is lifted from the pawl.
As part of the invention, the rotary latch interacts with the catch lever.
Only when the catch
lever assumes its releasing position, can the rotary latch escape its closed
position.
It has shown to be advantageous for the axes of the catch lever, release
lever, blocking pawl
and pawl to be arranged together in the lock case. In most cases the
aforementioned axes
are arranged in parallel to each other. This also applies to an axis passing
through or
accommodating the rotary latch.
The moment of inertia of the catch lever is designed in such a way that even
in the event of
a crash and the abnormal acceleration forces created during such an event,
hardly any
relative movement of the catch lever occurs. The rotary latch and the catch
lever do thus
remain at rest even in such a case, so that this also applies to the locking
mechanism as a
whole. Unintentional opening of the locking mechanism is thus excluded.
Also, the design is in most cases such that the inertia forces of the catch
lever created
during a crash exceed more or less easily any coupling forces to the actuation
lever unit. As
already explained, the catch lever is advantageously elastically coupled with
the release
lever via said spring. In case of a crash or accident, the inertia forces
acting on the catch
lever are significantly greater than any tensile forces created by the
coupling spring which
are, e.g. transferred by the deflected release lever onto the catch lever.
The catch lever is returned by a second spring, moving it into its blocking
position.
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Considering the fact that the catch lever is actuated during every normal
opening process, a
particularly reliable functioning is provided by a simple design. These are
the main
advantages of the invention.
Below, the invention is explained in more detail with reference to an
embodiment.
A motor vehicle door lock contains a locking mechanism consisting of a rotary
latch, a
blocking pawl and a pawl. The locking mechanism is arranged in a lock case.
The general arrangement also includes an actuation lever unit consisting of a
release lever
and a further or several further levers connected thereto. In order to open
the locking
mechanism from its closed state, the release lever must be rotated clockwise
around its axis
by the actuation lever unit. Such a rotation of the release lever causes the
release lever to
engage with one of its edges in a journal of the blocking pawl. The clockwise
movement of
the release lever during this process corresponds with the blocking pawl
carrying out a
counterclockwise movement around its axis.
As a result, the blocking pawl releases the pawl and the previously engaged
rotary latch.
The spring moves the rotary latch from its shown closed position by turning it
clockwise into
an open position and releases at the same time a previously engaged locking
bolt. The
locking bolt is connected to a motor vehicle door, which is also released
during this operation
and can be opened.
Apart from the blocking pawl, the pawl ensures that the locking mechanism is
being retained
in the closed position. The blocking pawl functions thus ¨ if you will ¨ as an
additional
safeguard of the rotary latch, in addition to the pawl.
According to the invention, the movement of the rotary latch from the blocking
position to the
releasing position (and back) is produced with the aid of a release lever,
during which a
catch lever is moved from its blocking position into a releasing position. The
catch lever is
thus a swivel lever rotatable around an axis. The catch lever is actually
designed as a two-
arm lever and contains a blocking arm and a compensation arm. The blocking arm
interacts
with the rotary latch already acted upon.
The catch lever and its axis are accommodated in the lock case together with
the locking
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mechanism. The same applies to the release lever and its axis. At the same
time, the
respective axes of, on one hand, the rotary latch and the blocking pawl and,
on the other
hand, the pawl and the release lever as well as ultimately the catch lever are
always
arranged parallel to each other. All axes extend mainly perpendicularly from a
base plane of
the lock case and are all anchored in the lock case.
It is apparent that the catch lever is coupled to the actuation lever unit by
means of an elastic
coupling in form of a spring. For this purpose, the spring in the embodiment
connects the
release lever to the catch lever by the spring engaging the blocking arm of
the catch lever.
The catch lever contains a cam or a deformation interacting with the counter
element on the
rotary latch. In the embodiment, the catch lever contains a recess on its
blocking arm. A cam
arranged on the rotary latch engages in this recess.
To change the blocking position of the rotary latch to the releasing position,
the catch lever
must carry out a counter-clockwise turn around its axis. The catch lever then
assumes its
releasing position. This counter-clockwise movement of the catch lever around
its axis is
caused by the release lever being turned clockwise around its axis in normal
operation to
open the locking mechanism. To achieve this, the actuation lever unit can be
acted upon
accordingly by a door handle, e.g. an internal door handle or external door
handle. This is
indicated by an arrow.
The acting on the actuation lever unit causes a deflection of the actuation
lever unit and thus
the deflected normal operation of the catch lever. Due to the coupling of the
catch lever to
the release lever by means of the spring, the catch lever is carried along
during the
clockwise rotation of the release lever around its axis. As a result, the
catch lever releases
the rotary latch.
As the described process and the clockwise rotation of the release lever act
at the same
time on the journal of the blocking pawl with the aid of the stop edge, the
blocking pawl is
synchronously activated and the pawl is automatically or by means of a further
contour on
the release lever lifted off the rotary latch. At the end of this process, the
rotary latch has
been released and can move from the closed position clockwise around its axis
and can
release the previously engaged locking bolt.
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If the actuation lever unit and thus the catch lever is not deflected, the
catch lever remains in
its blocking position and ensures that the rotary latch for the locking
mechanism is also being
acted upon in the direction of its blocking position. This means that the
catch lever remains
at rest and consequently also the rotary latch interacting with the catch
lever, with both
levers retaining their blocking position unchanged, thus retaining the rotary
latch in a closed
condition. This position of the normal operation is also maintained in the
event of a crash.
The inertia moment of the catch lever ensures that no relative movement of the
catch lever
occurs in case of a crash, so that the two catch levers and rotary latch
remain at rest in
relation to each other.
This even applies in the event that the actuation lever unit is deflected due
to applied
acceleration forces. As such, a deflection is expressly permitted by the
elastic coupling
between the actuation lever unit and the catch lever. This is ensured by the
spring arranged
, between the release lever and the catch lever. As already stated
above, the design of the
example is thus that any coupling forces between the actuation lever unit and
the catch lever
produced and applied by the spring are significantly weaker than the inertia
forces acting on
the catch lever. In other words, even in case of a deflection of the release
lever, the spring is
not able to deflect the catch lever, remaining in position due to its inertia
moment.
In another embodiment, the catch lever acts in the described way on the rotary
latch of a
locking mechanism not containing a blocking pawl, with the release lever
acting directly on
the pawl.
